High-capacity memory card and method of making the same

Abstract

A memory card assembly with a simplified structure. The memory card assembly has a memory card assembly a printed wiring board substrate and at least one integrated circuit unit mounted and electrically connected to the printed wiring board substrate. A rigid ring is fitted over a periphery of the printed wiring board substrate to encircle the integrated circuit die therein. Thereby, a dam with an open top is constructed over the printed wiring board substrate. A filler resin material is then filled within the open dam to cover the printed wiring board substrate and integrated circuit unit.

1. A memory card assembly, comprising:
 a printed wiring board substrate having upper and lower surfaces, the printed wiring board having a contact pad engageable with a reader device, the contact pad disposed on the lower surface, the printed wiring board defining an outer substrate periphery; 
 at least one integrated circuit unit mounted and electrically connected to the printed wiring board substrate; 
 a filler resin material applied over the printed wiring board substrate and the integrated circuit unit; and 
 a rigid retaining member defining an inner retaining periphery being less than the outer substrate periphery, the rigid retaining member having an inner sidewall fitted over the printed wiring board substrate, the retaining member being operative to retain the filler resin material as it is applied over the printed wiring board substrate and the integrated circuit unit, the rigid retaining member defining an outer periphery that is engageable to the substrate upon vertical translation, the inner sidewall defining a variable sidewall thickness along an intermediate portion of the inner sidewall and forming a notch in the vertical direction at approximately the center of the inner sidewall, the notch pointing outwards into the rigid retaining member. 
 
   
   
     2. The assembly of  claim 1 , wherein the integrated circuit unit includes a single flash IC die. 
   
   
     3. The assembly of  claim 1 , wherein the integrated circuit unit includes a stack of flash IC dies. 
   
   
     4. The assembly of  claim 1 , further comprising a controller integrated circuit mounted and electrically connected to the printed wiring board substrate. 
   
   
     5. The assembly of  claim 1 , wherein the memory card assembly includes a secure-digital card, a mini-secure-digital card, a micro-secure digital card, a multimedia circuit card, or a mini-multimedia circuit card. 
   
   
     6. The assembly of  claim 1 , wherein the inner sidewall of the retaining member is gradually inclined towards an outer sidewall thereof. 
   
   
     7. The assembly of  claim 1 , wherein the integrated circuit unit includes a TSOP leadframe package that comprises a flash integrated circuit therein. 
   
   
     8. The assembly of  claim 1 , wherein the retaining member has a height no less than the height of the integrated circuit unit. 
   
   
     9. The assembly of  claim 1 , wherein the rigid ring retaining member includes a center bar extending between two opposing sides thereof. 
   
   
     10. A method of fabricating a memory card assembly, comprising:
 a) mounting at least one memory integrated circuit unit on a printed wiring board substrate having upper and lower surfaces, the printed wiring board having a contact pad engageable with a reader device, the contact pad disposed on the lower surface, the printed wiring board defining an outer substrate periphery; 
 b) fitting a rigid retaining member over the printed wiring board substrate to form a dam in which the memory integrated circuit unit is located the rigid retaining member defining an inner retaining periphery being less than the outer substrate periphery, the rigid retaining member defining an outer periphery that is engageable to the substrate upon vertical translation, the rigid retaining member having an inner sidewall defining a variable sidewall thickness along an intermediate portion of the inner sidewall, and forming a notch at approximately the center in the vertical direction of the inner sidewall, the notch pointing outwards into the rigid retaining member; and 
 c) filling the retaining member with a filler resin material. 
 
   
   
     11. The method of  claim 10 , wherein step (a) includes providing the memory integrated circuit unit in the form of a single flash IC package. 
   
   
     12. The method of  claim 10 , wherein step (a) includes providing the memory integrated circuit unit in the form of a package of multiple flash IC's. 
   
   
     13. The method of  claim 10 , wherein step (a) further comprising mounting a controller IC on the printed wiring board substrate. 
   
   
     14. The method of  claim 10 , wherein step (b) comprises providing the retaining member with a height no less than a height of the memory integrated circuit unit. 
   
   
     15. The method of  claim 10 , wherein the inner sidewall is gradually inclined outwardly towards the printed wiring board substrate. 
   
   
     16. The method of  claim 10 , wherein step (b) further comprises providing the retaining member having a recessed inner sidewall. 
   
   
     17. A high-capacity memory card, comprising:
 a flash memory unit disposed on a printed wiring board substrate; 
 a filler resin covering the flash memory units; and 
 a rigid retaining member having an inner sidewall encircling the flash memory unit, the rigid retaining member defining an outer periphery that is engageable to the substrate upon vertical translation, the inner sidewall defining a variable sidewall thickness along an intermediate portion of the inner sidewall, and forming a notch in the vertical direction at approximately the center of the inner sidewall, the notch pointing outwards into the rigid retaining member, the retaining member being operative to retain the filler resin as it is disposed over the flash memory unit, wherein the retaining member outstands the flash memory unit by a height difference, and the filler resin on top of the flash memory unit has a thickness equal to the height difference. 
 
   
   
     18. The memory card of  claim 17 , wherein the retaining member includes a bar extending between two opposing points of the retaining member. 
   
   
     19. A memory card assembly, comprising:
 a printed wiring board substrate; 
 at least one integrated circuit unit mounted and electrically connected to the printed wiring board substrate; 
 a filler resin material applied over the printed wiring board substrate and the integrated circuit unit; and 
 a rigid retaining member having an inclined inner sidewall fitted over a periphery of the printed wiring board substrate, the inner sidewall of the retaining member being gradually inclined towards an outer sidewall thereof, and forming a notch in the vertical direction at approximately the center of the inner sidewall, the notch pointing outwards into the rigid retaining member, the rigid retaining member including a center bar extending between two opposing sides thereof, the rigid retaining member being operative to retain the filler resin material as it is applied over the printed wiring board substrate and the integrated circuit unit. 
 
   
   
     20. A memory card assembly, comprising:
 a printed wiring board substrate having upper and lower surfaces, the printed wiring board having a contact pad engageable with a reader device, the contact pad disposed on the lower surface, the printed wiring board defining an outer substrate periphery; 
 at least one integrated circuit unit mounted and electrically connected to the printed wiring board substrate; 
 a filler resin material applied over the printed wiring board substrate and the integrated circuit unit; and 
 a rigid retaining member defining an inner retaining periphery being less than the outer substrate periphery, the rigid retaining member having an inner sidewall fitted over the printed wiring board substrate, the retaining member being operative to retain the filler resin material as it is applied over the printed wiring board substrate and the integrated circuit unit, the rigid retaining member defining an outer periphery that is engageable to the substrate upon vertical translation, the inner sidewall defining a variable sidewall thickness along an intermediate portion of the inner sidewall and forming a notch at approximately the center of the inner sidewall, the notch pointing outwards into the rigid retaining member, wherein at least a portion of the inner sidewall is gradually inclined outwardly towards the printed wiring board substrate.